Minimum clinically important difference for drug effectiveness in an area of patient-oriented therapeutic goals in amyotrophic lateral sclerosis

Objective: In this review, we will examine the more common endpoints incorporated in randomized controlled trials (RCTs) and their strength of evidence, focusing on the definition of what constitutes a clinically meaningful change. We will also reflect on the perspective of patients and their families regarding the design of RCTs in amyotrophic lateral sclerosis (ALS). Methods: Authors performed a scoping review of the literature around clinical meaningfulness in the ALS field and the minimum clinically important difference to deem a treatment effective. Results: The use of survival as an RCT endpoint, as well as the ALS functional rating scale-revised slope, has been criticized, and their relevance for patients remains debated. Biomarkers are promising alternatives as surrogate endpoints, but currently, only cerebrospinal fluid and plasma neurofilaments have emerged as reliable and sensitive biomarkers of disease progression. Incorporating patients' preferences and priorities for their care when treatments are selected is important to minimize the burden of care and limit the potential harms of overtreatment. Patients' interest in and acceptance of a new therapy is also determined by its impact on their quality of life. Discussion and conclusion: While scientifically sound trials must be conducted, this must be balanced with patient expectations of limiting trial burden, duration and placebo usage. An important approach in uniting these diverging needs is the inclusion of people with ALS and their organizations to advise in the design and execution of clinical trials, facilitating the design of RCTs more focused on patients' expectations while retaining a high scientific rigor.